MOLECULAR ORDER AND MOBILITY WITHIN MEMBRANES MADE FROM FLUOROCARBON FLUOROCARBON AND FLUOROCARBON/HYDROCARBON DOUBLE-CHAIN ETHER AND AMIDEPHOSPHOLIPIDS/

The order of membranes formed by various ether-or amide-connected fluo rocarbon/fluorocarbon or mixed fluorocarbon/hydrocarbon double-chain p hosphocholines which derive, respectively, from glycerol or diaminopro panol or serine, has been investigated using fluorescence anisotropy o f TMA-DPH, and compared to that of membranes made from fluorinated or conventional ester-connected phosphatidylcholines. In the gel phase, m embrane order is almost not affected by the molecular structure of the phospholipid. By contrast, in the liquid-crystalline state, it decrea ses on going (i) from membranes made from the fluorocarbon/fluorocarbo n phospholipids to those formed by mixed fluorocarbon/hydrocarbon phos pholipids, then to conventional ones, (the rigidifying effects of the fluorinated tails, their number and length is thus becoming noticeable ) or (ii) from membranes made from fluorinated diamidopropano- or diam idoserinophosphocholines to those made from ester-or ether-connected g lycerophosphocholines. The ester-versus ether-connection or 1,2- versu s 1,3-connection of the chains on glycerol have no detectable impact o n membrane order. (C) 1997 Elsevier Science Ireland Ltd.